junit--基于测试开发和cobertura框架

1.什么是基于测试的开发

正常的开发流程：编码-->测试-->重复-->提交

基于测试的开发流程：测试-->编码-->重复-->提交

先写了测试之后，由于测试覆盖率要求为100%，所以就会让代码中可能存在的分支都进行测试，这样过先写测试单元，可以为将来的代码提供一种有效的参考

基于测试的开发例子：

编写接口:

package com.qunar.service;import com.qunar.model.User;public interface IUserService {public void add(User user);public void delete(String username);public User loader(String username);public User login(String username, String password);}

2.针对接口进行测代码的编写 注意要覆盖每个方面

package com.qunar.service;import static org.junit.Assert.*;import org.junit.Before;import org.junit.Test;import com.qunar.model.User;import com.qunar.model.UserException;import com.qunar.service.impl.UserServiceByMap;public class TestUserService {private IUserService us;private User baseUser;@Beforepublic void setUp() {// initus = new UserServiceByMap();baseUser = new User("admin", "123", "管理员");}@Testpublic void testAdd() {User user = baseUser;us.add(user);User user2 = us.loader("admin");assertNotNull(user2);assertTrue(user.equals(user2));}@Testpublic void testDelete() {us.add(baseUser);User tUser = us.loader(baseUser.getUsername());assertNotNull(tUser);us.delete(baseUser.getUsername());tUser = us.loader(baseUser.getUsername());assertNull("删除的用户还存在",tUser);}@Testpublic void testLogin() {us.add(baseUser);String username = "admin";String password = "123";User user = us.login(username, password);assertTrue(user.equals(baseUser));}@Test(expected = UserException.class)public void testNotExistsUserLogin() {us.add(baseUser);String username = "admin1";String password = "123";us.login(username, password);}@Test(expected = UserException.class)public void testPasswordErrorUserLogin() {us.add(baseUser);String username = "admin";String password = "1234";us.login(username, password);}}

3.编写实现类

package com.qunar.service.impl;import java.util.Map;import com.google.common.collect.Maps;import com.qunar.model.User;import com.qunar.model.UserException;import com.qunar.service.IUserService;public class UserServiceByMap implements IUserService {private Map<String, User> map = Maps.newHashMap(); @Overridepublic void add(User user) { if (loader(user.getUsername())!=null) {throw new UserException("用户名已经存在");} map.put(user.getUsername(), user);}@Overridepublic void delete(String username) {map.remove(username);}@Overridepublic User loader(String username) {// TODO Auto-generated method stubreturn map.get(username);}@Overridepublic User login(String username, String password) {User user = loader(username);if(user==null){throw new UserException("用户名不存在");}if(user.getPassword()!= password){throw new UserException("用户密码不正确");}return user;}}

运行testCase 全部通过

如果在实现类中，当删除用户名为admin的时候不允许删除，如下所示

public void delete(String username) {if(username.equals("admin")){return ;}map.remove(username);}

再次运行测试代码：

java.lang.AssertionError: 删除的用户还存在at org.junit.Assert.fail(Assert.java:93)at org.junit.Assert.assertTrue(Assert.java:43)at org.junit.Assert.assertNull(Assert.java:551)at com.qunar.service.TestUserService.testDelete(TestUserService.java:39)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:606)at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45)at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:42)at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:263)at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:68)at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)at org.junit.runners.ParentRunner.run(ParentRunner.java:300)at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

这样可以明确的指出那里出了错误

2.cobertura 的使用

1）首先修改工程的pom.xml文件 加入如下代码

<reporting>        <plugins>            <plugin>                <groupId>org.codehaus.mojo</groupId>                <artifactId>cobertura-maven-plugin</artifactId>                <version>2.5.1</version>            </plugin>        </plugins>    </reporting>

首先运行“mvn cobertura:help”， 如果不能运行，请添加以下仓库

    <pluginRepositories>        <pluginRepository>            <id>Codehaus repository</id>            <url>http://repository.codehaus.org/</url>        </pluginRepository>    </pluginRepositories>

cobertura插件的命令

mvn cobertura:help          查看cobertura插件的帮助mvn cobertura:clean         清空cobertura插件运行结果mvn cobertura:check         运行cobertura的检查任务mvn cobertura:cobertura     运行cobertura的检查任务并生成报表，报表生成在target/site/cobertura目录下cobertura:dump-datafile     Cobertura Datafile Dump Mojomvn cobertura:instrument    Instrument the compiled classes

到项目根目录下运行mvn cobertura:cobertura 将会插桩class文件、测试、生成覆盖率报告

我的测试代码生产的报表如下：